A drawn-out primary could sap the eventual nominee of resources and hurt their chances against Hagan. Most recent polls show a close general-election race.

This week doesn't bring all good news for Brannon, however. Two investors in a technological start-up he served on the board of are charging that he misled them into investing in that company, according to court documents first reported by WRAL and also obtained by The Hill. Brannon will be in civil court next week to answer the allegations.

His campaign downplayed concerns about the lawsuit.

"I'm looking forward to my day in court and I'm confident it will be resolved," Brannon said in a statement via his campaign manager.